Researchers at the Massachusetts Institute of Technology have developed a way to use 3D printing to make cable-driven mechanisms. These mechanisms replicate the motion of, say, a human finger. A cable is strung through a set of parts that are like finger bones. Pulling on the cable causes the mechanical finger to curl.

The researchers’ technique, called X-strings, uses a multi-material 3D printer to make all of the mechanism’s parts, in their desired locations, in one step. This includes the cables and joints that enable the assembly to move.